Paratrooper34

Ok, got a problem that has me stumped.

I have a 2005 GT automatic with 35,000 miles. I put an Airraid CAI and a tune with a Bama S4 tuner (93r) back in January. About 2 months ago I started the car up to warm it and when I came back out to it, it was showing "Engine Failsafe Mode" (EFM) on the display. Never saw that before, had no idea what it was. So I turned the car off and back on and it was gone.

Since that time, I have been seeing it more often (occasionally). If I turn the car off and back on, it goes away. In addition to that, the car has died on me a couple of times (it lost power, displayed EFM, and then died). I asked a friend and he said maybe the crank or cam sensor needed to be replaced. I decided to try out the code reader on the Bama S4 and it said no codes. So I switched the tune over to the 93s. I haven't run the car on it yet other than to idle in the garage.

So I am at a loss over this. Something must be wrong for the car to display the EFM warning and cutoff on me, right? But no codes on the Bama. Anybody have any insight into this?

Thanks in advance!

jwog666

typically the failsafe mode(sometimes combined with a wrench light) is an indicator of a throttle by wire system concern, these will not always set a code. the fault is usually intermittent and that is why after a key cycle you can start it and drive normally again. with no codes and it being intermittent, this concern will be very hard to diagnose. if after the fault and messege occurs does the vehicle loose throttle response? if so you are probably looking at a throttle body or accelerator pedal assembly issue. good luck

Paratrooper34

[QUOTE=jwog666;8487543]typically the failsafe mode(sometimes combined with a wrench light) is an indicator of a throttle by wire system concern, these will not always set a code. the fault is usually intermittent and that is why after a key cycle you can start it and drive normally again. with no codes and it being intermittent, this concern will be very hard to diagnose. if after the fault and messege occurs does the vehicle loose throttle response? if so you are probably looking at a throttle body or accelerator pedal assembly issue. good luck[/QUOTE

Thanks for the quick reply, jwog, looks like you are on to it. Here is some new info:
Drove it to work this morning. FEM light came on after a couple miles or so. Turned it off and on, it went away. A minute or two later, it came back on again only this time it was accompanied by the check engine light. Would not go away by turning it off/on.
Brought my scanner to work and came up with these two codes: P2106 and P2135.
P2106 is "Throttle actuator control system - forced limited power"
P2135 is "Throttle/pedal position sensor/switch "A"/"B" voltage correlation.
Would throttle position sensor be the right choice?

jwog666

yes, the entire throttle pedal assembly should be replaced, assuming that there is not a concern with the wiring(its more common that the pedal be faulty, but there always is a chance of bad wiring), i have changed many pedals that have failed just like yours

Paratrooper34

[QUOTE=jwog666;8487554]yes, the entire throttle pedal assembly should be replaced, assuming that there is not a concern with the wiring(its more common that the pedal be faulty, but there always is a chance of bad wiring), i have changed many pedals that have failed just like yours[/QUOTE

I checked rockauto.com for the part and I see two that are related to what you said. There is a Accelerator Pedal Position Sensor (attaches to the accelerator pedal?) and a Throttle Position Sensor (not sure where that goes). In your reply, are you referring to the Accelerator Pedal Position Sensor?

jwog666

the accelerator pedal position sensor is the one you need, the p2106 is to tell you that there is a throttle system problem and that idle is forced, the p2135 is to tell you that the throttle pedal sensor (there are actually 2 in the pedal a and b they have inverse voltages and need to indicate the same % of throttle as each other) is faulty.

Paratrooper34

Ok, got it! Thanks so much for your help! I will let you know how it turns out. I see you are far away from me, but if you are ever in New England, beers on me.

jwog666

lol no problem. i like getting to the bottom of problems

Paratrooper34

UPDATE....

Ok, got the part swapped out today. Cleared the codes out and the check engine light is gone. Took it out for a ride and damn it, the car died on the road while driving. Lost power and shut off. This is what it was doing before. Turned it back on, it was fine until it happened a little while later as I was pulling into my driveway. No check engine light, nothing. Now I am really stumped.

jwog666

it could be a wiring issue from the pcm to the sensor